Projection type cathode ray tube

Abstract

A projection type cathode ray tube which has excellent optical characteristics and endurance thanks to the enhanced cooling effect and is manufactured efficiently at low cost. The thickness of a panel is uniform throughout the panel except its peripheral portion contacting a coupler (a cooling liquid holder). The cooling effect on the panel by a cooling system is uniform throughout the entire panel, enhancing the optical characteristics and endurance of the panel. In the manufacturing process applying heat to the panel, a reduction in the cooling temperature and the cooling time causes no difference in temperature, achieving uniform cooling. The panel except its peripheral portion is a curved portion in the concave form. For the interest of higher adhesion, it is sufficient to polish only the peripheral portion adhering to the edge of the opening on the rear side of the coupler, which reduces the polishing time.

What is claimed is:  
     
         1 . A projection type cathode ray tube comprising: 
 a main body comprising a panel on which at least phosphor is provided, the panel being formed in the inwardly curved form with a uniform thickness; and    a cooling system which has an opening facing the panel, and is filled with a cooling liquid for cooling the panel so that the cooling system makes contact with the panel through the opening.    
     
     
         2 . A projection type cathode ray tube as claimed in  claim 1 , wherein the panel is mounted on the front surface of the panel with a sealing member in between, and only a portion of the panel which contacts the sealing member is polished.  
     
     
         3 . A projection type cathode ray tube as claimed in  claim 2 , wherein polishing is performed using an abrasive containing cerium oxide.  
     
     
         4 . A projection type cathode ray tube as claimed in  claim 2 , wherein the peripheral portion of the outer surface of the panel is a substantially planar surface.  
     
     
         5 . A projection type cathode ray tube as claimed in  claim 1 , wherein the sealing member is an adhesive containing silicone resin.  
     
     
         6 . A projection type cathode ray tube as claimed in  claim 5 , wherein the adhesive contains silicone rubber.  
     
     
         7 . A projection type cathode ray tube as claimed in  claim 1 , wherein the cooling system has another opening which is at the position facing the opening and is blocked by a lens mounted on the cooling system.  
     
     
         8 . A projection type cathode ray tube as claimed in  claim 7 , wherein the lens is mounted on the cooling system with an O ring in between.  
     
     
         9 . A projection type cathode ray tube as claimed in  claim 1 , wherein the cooling liquid held in the cooling liquid holder is a clear liquid having a refractive index substantially equal to the refractive index of the panel.  
     
     
         10 . A projection type cathode ray tube as claimed in  claim 9 , wherein the clear liquid is a mixed solution of ethylene glycol and glycerin.